Technical Field
The present disclosure of invention relates to a curved liquid crystal display (“LCD”) panel. More particularly, it relates to a curved LCD panel capable of enhancing a display quality.
Discussion of Related Technology
In recent years, as the liquid crystal display device (“LCD”) has come to be popularly used as a display device for television receivers and other multi-user applications, the screens of such liquid crystal display devices have been trending towards becoming increasingly bigger. But a problem with such increasingly larger (e.g., wider) television LCD screens is that the quality of viewing experience changes substantially between when a centered user views the screen while focusing on the center portion of the screen and when the centered user focuses his/her view to the left or right edges of the wide display screen. The problem can be worse for a second user situated closer to the left or right edge of the wide display screen and trying to focus eyesight on the much further away (and more angled relative to the screen normal) opposite edge of the wide display screen.
Curved display screens have been proposed a solution to this problem. In this specification, the technical term “viewing angle” is used and is defined as the acute or right angle formed between the line of focusing sight of the viewer viewing the horizontally wide screen and a horizontal tangent line that is tangent to the curved spot on the screen where the user's line of sight intersects with the screen surface. In other words, the “viewing angle” of a horizontally centered user who focuses on the center of the screen is the right angle (90 degrees) while the “viewing angle” of the same user when focusing on a right edge or a left edge is, for the case of an almost flat screen, an acute angle (less than 90 degrees). The difference in “viewing angle” between when the centered user views the center and when he/she focuses on the left/right edge is defined as, and is used herein as being the “viewing angle difference”. More specifically, if the “viewing angle” for the left or right edge is 60 degrees, then the “viewing angle difference” will be the complement of that, namely, 30 degrees. If sameness of viewing experience is desired under these terms, then the “viewing angle difference” should be reduced towards zero (0) degrees.
Furthermore, another problem with flat-type large-scale television LCD screens is that glare off the screens also increases. Both the side glare problem and the problem of difference in viewing angle can be corrected by curving the screen into a concave shape.
Uniformity of viewing experience as between on-center focus and towards-edge focus also depends on uniformity of thickness of the liquid crystal material in the respective portions the screen (e.g., the screen center and screen extreme left and right side edges). Typically, so-called, column spacers having a uniform cross-section over their respective heights (e.g., cylinder shaped) are formed on one of the upper and lower substrates of a LCD panel so as to maintain a uniform cell gap of a liquid crystal layer across the full width of the panel. In a case of a curved LCD panel having a color filter on array (“COA”) type where a color filter layer is formed on the lower substrate, a step variation can be generated due to how the consistent-in-cross-section column spacers engage as between the opposed inner surfaces of the upper and lower substrates, so that display defects of the LCD panel are generated as a function of the shapes and/or a positions of the column spacers.
In the case of curved LCD panels, display color defects such as bluish or yellowish color tinting can occur due to a misalignment between an upper substrate and a lower substrate. This is mainly because changes of cell gap are generated in panels structured to have same, consistent-in-cross-section column spacers formed everywhere on a COA type LCD panel.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.